Grape seed extract: the first plant-based fining agent endogenous to grapes

Background and Aims There is a growing interest in finding alternative wine fining agents to replace potentially allergenic 8 animal- and plant-derived proteins. In this context, the potential use of grape-derived fining agents would be beneficial as they would not introduce additional potentially allergenic products to the finished wine. In this project, grape seed flour, a by-product of the grape oil seed industry, has been used to prepare a grape seeds extract (GSE) to be tested as a novel wine fining agent. Methods and Results: The fining performances of GSE were compared with those of patatin, pea protein, PVPP, K14 caseinate (in a white and in a rosè wines), ovalbumin and gelatin (in a red wine). Turbidity reduction, effects on wine color, polyphenolic content, browning potential and wine sensory attributes were determined. GSE was effective in decreasing white wine turbidity when compared to K-caseinate. In red wine, GSE removed some anthocyanins and proanthocyanins, while wine colour was only slightly affected. The greatest GSE effect was observed on the organoleptic properties of the treated wines, as it drastically reduced the vegetal notes on the rosé wine and improved the overall taste of the red wine as a result of the reduction in both acidity and astringency. Conclusions: GSE can be considered a valid allergen-free alternative to the most common wine fining agents.